At 7am on a hot Thursday morning, Kgalalelo Ntsepe is number 63 in the queue. An hour later almost 100 more people have crowded into the waiting room at the Infectious Diseases Care Clinic (IDCC) at Princess Marina Hospital in Gaborone, Botswana. Some walk through the door, others are carried in by relatives. Vans arrive with more men, women and children from towns and villages as far away as 373 miles from the capital.

Kgalalelo will have to wait several more hours before she sees one of five doctors for her three-monthly check-up. Then she will join another queue to refill her prescription for the two antiretroviral (ARV) drugs she takes at 7am, 7pm and at bedtime every day. The 32-year-old is one of about 5,000 people (over 4,000 adults and just under 1,000 children) who are registered at the IDCC for ARV therapy. This clinic, currently one of 10 ARV distribution sites in Botswana, is the largest single distributor of this therapy in Africa. By the end of 2004, another 20 IDCCs will be opened around the country.

At present some 9,000 Batswana (citizens of Botswana) receive free ARV treatment from government. At 35.4 per cent among 15- to 49-year-olds, Botswana has the highest HIV prevalence rate in Africa. Approximately 300,000 people in a population of just under 1.7 million are estimated to be HIV-positive. Of these, 110,000 should be receiving ARV treatment. By the end of the year, 10,000 HIV-positive Batswana will be on the programme. By the end of 2004, it will be expanded to include a further 15,000.

The cost of the ARV therapy programme to government in 2003 is 38.4m pula (about $8.1m), according to the government's National Strategic Framework for HIV/Aids 2003-2009. Asked whether this programme is sustainable, Dr Kereng Masupu, an epidemiologist and consultant with the National Aids Coordinating Council (Naca) says: 'The question is what would have happened if we had not done it. Is that sustainable? The answer to that is no. It is not sustainable if you don't do anything.'

The government began rolling out free ARV therapy in January 2002 with the aim of extending the life expectancy and increasing the productivity of people living with HIV/Aids, thus lowering the burden on the economy and on society. Although Botswana is one of the wealthiest countries in Africa (thanks to its diamond resources), it relies on the assistance of international partners to manage and finance the ARV programme, most notably the African Comprehensive HIV/Aids Partnership (Achap). This public-private partnership between the Bill and Melinda Gates Foundation, the US pharmaceutical company Merck and the Botswana government, supports, initiates and evaluates HIV/Aids programmes in Botswana and provides technical and financial support. Achap commited $45m to HIV/Aids programmes at the end of 2002.

Eighteen months into the ARV programme, it is still too early to quantify its impact. Dr Howard Moffat, superintendent at Princess Marina Hospital, one of two referral hospitals in Botswana, said the ARV programme has not yet had a significant effect on the hospital. It would take a few more years for the impact to be noticeable 'because of the huge backlog', he says. About 19,000 residents of the Gaborone area should be receiving therapy. 'Many are not even aware of their HIV status and not all are ill, but they are on the precipice.'

The occupancy rate in the 530-bed hospital is 'well over 100 per cent', says Moffat, and 'Aids dominates everything.' In the adult medical ward, 70 to 80 per cent of the cases are Aids-related. 'We hope that, with time, the huge numbers of patients with Aids-related illnesses will drop substantially. We hope for a 10-year period of calm within a couple of years. Because this is new and no country has done this before, at least not on this magnitude, it's hard to work out what the impact will be.'

For Kgalalelo the impact of the ARV therapy is clear: the drugs have brought about a dramatic improvement in her life. Those on the programme play an important role in dispelling people's fears regarding the side effects of ARVs and in reducing the stigma shrouding people living with HIV/Aids. At least partly because of the drugs, she was crowned Miss HIV Stigma-Free in September.

The contest, in its second year, was organised by the Centre for Youth and Hope, where Kgalalelo works as an HIV/Aids counsellor. The aim of the competition, in which 16 women vied for the title this year, is to fight the stigma that has become such a formidable obstacle in the fight against Aids. Being open about her status and speaking in public about HIV/Aids is one of Miss HIV Stigma Free's duties.'Some people said, "I don't know what the judges were looking for. These people are not beautiful." I have no problem with that. I feel beautiful. It [the contest] has changed my life.'

So did the ARVs. Kgalalelo weighed 48 kilos, had a CD4 count of 220 and a viral load approaching 14,000 before she joined an ARV therapy trial managed by the Harvard-Botswana partnership in August 2001. She was diagnosed HIV-positive in July 2001 after twice leaving a clinic before getting tested. 'I was scared, very scared. At the first appointment I read a pamphlet on the symptoms of HIV/Aids when I was in the queue. Everything which I saw in that pamphlet was happening in my body.'

Like most HIV-positive Batswana, she waited until she was very sick until she finally was tested. The average CD4 count of people registering for the ARV therapy programme is between 50 and 60. Anyone with a CD4 count of less than 200 qualifies for the government programme. Her first course of treatment caused severe side effects, but she remained on the programme. She now takes Combivir (AZT and 3TC) and Stocrin - a total of five tablets a day - and experiences no side effects. 'I feel fit and strong. I can do anything everyone else does.' Today her CD4 count is close to 600, her viral load is undetectable and she weighs almost 73 kilos. The compliance rate among the patients receiving ARV treatment at Princess Marina is around 95 per cent, disproving the claim that poor Africans cannot follow a strict treatment regimen.

The Botswana government knows that the eyes of the world, at the very least the eyes of their sub-Saharan neighbours, are on its ARV treatment programme, which has been named Masa ('new dawn' in Sesotho). But Botswana has several advantages over its neighbours: it is a relatively wealthy country which is heavily government-led, and it has a small, homogenous population. No model, not even Masa, can be replicated exactly in other countries, experts agree. Naca's Masupu says: 'If I were an adviser in another African country, I'd say, this is practical for Africa, it can be done. But I'd also say not to replicate it exactly, because we did it the expensive way. We had no point of reference.' He recommends integrating the ARV distribution into the health system, using existing resources.

Some important lessons can be drawn from the Botswana experience. One of them is not to be paralysed into inaction by waiting until all systems are in perfect order before rolling out ARV therapy. Dr Ernest Darkoh, operations manager of Botswana's ARV programme, argues that the ability to scale up quickly and being flexible in terms of who can do what job are two key factors. Botswana is using nurse practitioners in roles doctors would fill in Europe, for example. The biggest problem, he says, is the weak public health system. HIV/Aids, he says, 'highlights deficits' in terms of human resources, infrastructure and data collecting as well as monitoring and evaluation processes.

But Dr Kwame Ampomah, UNAids country coordinator in Botswana, argues that 'if Botswana, with all its resources and good governance doesn't make headway [in the fight against Aids] in the way we hope, it doesn't mean another country with fewer resources can't make it'. Any country that wants to provide ARVs must 'recognise that people are the instruments of development.Their survival is important to the future of the country. (Botswana's ARV programme) is a good example of bold decision making.'

Darkoh says countries must find a model suitable to their particular set of circumstances. He argues for 'lean, minimalist' and community-based models 'which put people in charge of their own care as much as possible'. Masa uses a 'buddy system'. Those on ARV therapy ask a friend or relative to remind them daily to take their medication. This, too, helps break down the stigma.

Darkoh welcomes Botswana's recent announcement that patients at clinics and hospitals will be routinely tested for HIV from next year. Their consent is still required, but instead of choosing to have an HIV test, they have to chose not to have one. Even without routine testing in place, he has seen 'strong evidence' of more people coming forward for HIV tests, motivated by the incentive of ARVs.

'Every time I come to the clinic there are more people,' says Kgalalelo. 'They ask me questions. "What do you do to get like that? You look so fat!" I have seen a lot of people who come here [to the clinic] dying. And then they are alive again. Even if the government says they have no more money, I will save money so I can supply myself, because I have seen that there is life in these tablets.'